Latch



W. F. HALL. Latch (Jo Mddel.)

N. PETERS, FHOTO-U NOGRAPHER, WASH NGTON D C UNITED STATES PATENT OFFICE.

WILLIAM F. HALL, OF BOSTON, MASSACHUSETTS.

LATCH.

SPECIFICATION forming part of Letters Patent No. 231,561, dated August 24, 1880.

Application filed May 31, 1880. (No model.)

To all whom it may concern Be it known that I, WILLIAM F. HALL, of Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Mortise-Latches, of which the following is a specification.

Sliding bolts for mortise-latches usually have a simple inclined head, the incline serving as a slide, which, when the door is being closed, comes in contact with the latch-plate and allows the latch to be pushed in by wedge action. This requires considerable force to be exerted by the person closing the door.

The above device has been improved upon by inserting in the head of the latch a bentlever, one end of which comes in contact with the latch-plate, while the other end comes in contact with the inner face of the casing of the latch, so that when the door is being closed this bent lever pries the latch back.

My invention consists in combining with the head of the bolt a. spur-wheel, said wheel be ing hung upon an axis within the head of the bolt, so as to be free to revolve, and in use it is actuated by the latch-plate, the edge of which, coming in contact with one spur, throws the next following spur against the face of the latch-plate. There it acts partly as a lever and partly as a roller, so that the boltis thrown back by a leverage that has a rolling friction and is easily worked.

The advantages of the spur-wheel device are, that no spring is required, that the device is very simple and cheap, and is under all circumstances in working position, and on account of the wear being distributed over all the points of the spur-wheel it is very durable.

In the drawings, Figure 1 is a perspective view, showing my invention as applied to a door and easing. Fig. 2 is a horizontal section through the center of the latch. Fig. 3 is a vertical section of the latch. Fig. 4 is a perspective view, showing a part of the case of the latch.

A represents the door, into which the mor tise-latch is fitted. Bis the door-casing. 0 represents the face-plate of the casing of the latch, and D the casing proper.

The latch-bolt D is made as shown in Figs. 2 and 3-that is, its shank d is on line with the center of the head d, so that the bolt may be reversed in order to make the latch fit a left or right hand door. This latch is with drawn by means of a finger-lever, E, which acts upon a bent lever, E, and through said lever E upon the latch-boltitself. (See Fig. 3.)

F is a spring, which serves to throw the bolt forward. Instead of the above it may be operated by any of the well-known devices for that purpose.

The head of the latch-bolt is slotted, as shown in Figs. 1 and 3, and in this slot aspurwheel, K, is hung on a pivot, L, (see Figs. 2 and 3,) about which it can freely revolve. This spur-wheel acts as follows: When the door is being closed, as shown in Fig. 2, one of the spurs of the wheel K will comein contact with the edge H of the latch-plate. This will cause the wheel to revolve and bring the next spur in contact with the face H of the latch-plate. Continued motion of the door causes the spurwheel to revolve and by a rolling friction easily force the latch-bolt back, and there hold it until the openingin the latch-plateis reached.

As the spur-wheel K is larger in diameter than the thickness of the head of the latchbolt, it becomes necessary to cut away a part of the face-plate U to allow free motion of the wheel K, and as this cutting away weakens the face-plate at that point I am obliged to re-enforce it by forming on its back re-enforcing housings M M. (See Figs. 2 and 4.) These housings add sufficient] y to the strength of the face-plate to give it the required stiffness.

I claim as my invention The combination of the latch-bolt D and the spur-wheel K, journaled therein, with the latch-plate H H, all operating together substantially as described, and for the purpose set forth.

WILLIAM F. HALL.

Witnesses FRANK G. PARKER, J AS. W. J OHNSON. 

